Here's a breakdown:
* Heels: The back part of a boot.
* Going heeled: Implies having a pistol secured to the heel of the boot.
* Significance: In the Old West, carrying a firearm was essential for self-defense and survival. It was common practice, and "going heeled" indicated preparedness and a certain level of toughness.
So, if someone said they were "going heeled," it meant they were armed and ready for whatever might come their way.